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Keywords:

  • Intima media thickness;
  • lipoprotein-associated phospholipase A2;
  • metabolic syndrome;
  • type 2 diabetes mellitus

Eur J Clin Invest 2011; 41 (8): 820–827

Abstract

Background  A recent meta-analysis showed that both plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) mass and activity independently predict cardiovascular events. Notably, Lp-PLA2 activity but not mass was found to be a determinant of cardiovascular outcome in type 2 diabetes mellitus. We questioned whether relationships of carotid intima media thickness (IMT), a measure of subclinical atherosclerosis, with Lp-PLA2 mass differ between diabetic and nondiabetic subjects.

Materials and methods  Relationships of IMT with plasma Lp-PLA2 mass (turbidimetric immunoassay) were compared in 74 patients with type 2 diabetes and in 64 nondiabetic subjects.

Results  IMT was increased (= 0·016), but plasma Lp-PLA2 mass was decreased in patients with diabetes compared to nondiabetic subjects (277 ± 66 vs. 327 ± 62 μg L−1, < 0·001). In nondiabetic subjects, IMT was correlated positively with Lp-PLA2 (r = 0·325, < 0·009); multiple linear regression analysis confirmed an independent association of IMT with Lp-PLA2 (ß = 0·192, = 0·048). In contrast, IMT was unrelated to Lp-PLA2 in patients with diabetes (r = 0·021, = 0·86), and the relationship of IMT with Lp-PLA2 was different in diabetic and control subjects (< 0·001). The relationship of Lp-PLA2 with the total cholesterol/high-density lipoprotein (HDL) cholesterol ratio also differed between diabetic and nondiabetic subjects (< 0·001).

Conclusions  Plasma Lp-PLA2 may relate to early stages of atherosclerosis development. In diabetes mellitus, in contrast, the association of IMT with plasma Lp-PLA2 mass is abolished, which could be partly ascribed to redistribution of Lp-PLA2 mass from apolipoprotein B-containing lipoproteins towards HDL. These findings raise questions about the usefulness of plasma Lp-PLA2 mass measurement as a marker of subclinical atherosclerosis in type 2 diabetes mellitus.